Cities in Europe and Asia that are actually healthy, and have rejected car culture, don't have these tunnel thingies. Instead of moving pedestrian traffic away from streets, they improve their streets to make them friendly to pedestrians. The idea that climate issues necessitate this kind of divorce from the outdoors would be a strange concept indeed to people in Barcelona and Helsinki alike.
This is in fact a classic, 80s-90s North American car-infested big city band-aid. Leave the streets for the cars, leave the tiny sidewalks for the homeless and the trash, connect office buildings and plazas with pathways so the nine-to-fives can drive or subway in, go for their lunch or whatever, then drive/subway out without meeting the poors (because who else lives downtown anyway?) Et voila! Who needs to make downtowns actually liveable after all.
This is in fact a classic, 80s-90s North American car-infested big city band-aid. Leave the streets for the cars, leave the tiny sidewalks for the homeless and the trash, connect office buildings and plazas with pathways so the nine-to-fives can drive or subway in, go for their lunch or whatever, then drive/subway out without meeting the poors (because who else lives downtown anyway?) Et voila! Who needs to make downtowns actually liveable after all.